Method for the production of salmon growth hormone using a synthetic gene

Abstract

High protein content feed or hormonal steroids have been added to fish feed in order to elevate the efficiency of the feed. However, the steroids remain in the fish and may be detrimental to those who eat the fish. The invention relates to a method for the production of salmon growth hormone, which enhances the efficiency of the feed without the above side effects, using a synthetic gene in yeast or E. coli. It has been found that salmon growth hormone may be produced economically and in bulk in yeast or E. coli by gene manipulation technology.

We claim: 
     
       1. A process for the production of salmon growth hormone by culture of a eukaryotic microorganism expressing said salmon growth hormone from a recombinant plasmid, the improvement which comprises: 1) producing a yeast strain containing a salmon growth hormone gene by transforming said yeast strain with the vector pCl/1-SGH, said vector being described in FIG. 5;   2) culturing said transformed yeast in medium comprising Yeast Nitrogen Base without amino acids, Leu- supplements and glucose;   3) diluting the culture of step 2 into a medium comprising peptone, yeast extract and glucose and further culturing the cells;   4) adding to the culture ethanol and further incubating the cells; and   5) separating the yeast cells from the culture medium and collecting the salmon growth hormone from within the cells, wherein said salmon growth hormone is obtained in a yield of at least 5% of total yeast protein.   
     
     
       2. The process of claim 1, wherein the yeast strain that is transformed is DCO4. 
     
     
       3. A process for the production of salmon growth hormone by culture of a microorganism containing a recombinant plasmid providing expression of the salmon growth hormone, the improvement in which comprises: 1) transforming an E. coli strain with the plasmid ptrp 322 HSGH, said plasmid being described in FIG. 6;   2) culturing the transformed bacteria obtained in step (1) in LB medium containing an effective amount of ampicillin to prevent the growth of bacteria lacking the ptrp 322 HSGH plasmid;   3) diluting the culture of step (2) in medium;   4) adding to the culture of step (3) indole acrylic acid and continuing the culture; and   5) separating the bacteria from the culture medium and collecting the salmon growth hormone from within the bacteria, whereby said salmon growth hormone is obtained in a yield of 20% or greater of total E. coli protein.   
     
     
       4. The process of claim 3, wherein the E. coli strain that is transformed is W3110.